The present invention relates to TV (television) or radio control systems, and more specifically to the development and testing (debugging) of such systems. It finds particular application in a broadcast and reception system for use in digital interactive satellite television system. However, it will be realized that it is not limited to that system or systems of that type, but is applicable more generally to a variety of TV and/or radio systems, including for example those capable of broadcasting software.
A TV control system has been developed which is transmitted over satellite or cable links. Each end user has a receiver/decoder which receives control information, which can then be used for a variety of tasks such as reviewing TV programme listings, setting up home banking interactions, answering quiz questions relating to programmes being transmitted, and so on.
The digital TV system is an interactive system using a DVB/MPEG2 technique, which involves compressing the audio signals, data, and video images being transmitted. The MPEG system can also accommodate a considerable quantity of information of a xe2x80x9cprivatexe2x80x9d nature, i.e. not directly associated with the main programme being transmitted. This private sub-channel can be used by the broadcast supplier to transmit information such as TV programme listings.
The receiver/decoder can potentially require a large number of control functions or programs, which would require a large amount of memory to store them. Also, the broadcast supplier may wish to introduce further control programs, and may wish to update existing control programs. The system is therefore designed to allow the control programs to be broadcast repeatedly by the broadcast supplier (using the private sub-channel). The receiver/decoder has built into it an initial control program which performs an initializing or boot procedure, but then picks up from the broadcast signal whatever particular further control programs it needs to respond to the particular requirements of its user.
This means that the broadcast supplier can update existing control programs and introduce fresh ones extremely easily; the resulting improved and new services will automatically be immediately available to all users. However, such modification or development of services (control programs), carries with it its own problems and dangers. A particular problem or danger is that of errors (bugs). It is very important for the incidence of bugs to be kept extremely low, since any bugs will be broadcast to all users and can thus quickly cause widespread dissatisfaction and irritation.
The main aspect of the present invention is concerned with the development of control programs with rapid and effective fault (bug) detection.
Accordingly the present invention provides a method of developing, on a computer workstation, a control program for a broadcast digital television or radio system in which a receiver/decoder extracts broadcast control programs from the broadcast television or radio signal and controls a television or radio set in response thereto, the method comprising: coupling the workstation to a receiver/decoder-type unit which substantially duplicates the receiver/decoder with a television or radio set coupled thereto; developing the control program on the workstation; passing the program to the receiver/decoder-type unit; feeding an MPEG digital television or radio signal to the receiver/decoder-type unit; running the program on the receiver/decoder-type-unit; passing control signals from workstation to the receiver/decoder type unit to control the running of the program thereon; the receiver/decoder type unit and the program responding to the control signals and returning test signals to the workstation.